diff --git a/migrations/1781000000005_reconcile-user-profile.js b/migrations/1781000000005_reconcile-user-profile.js
new file mode 100644
index 0000000..f7d4ea9
--- /dev/null
+++ b/migrations/1781000000005_reconcile-user-profile.js
@@ -0,0 +1,191 @@
+/**
+ * Reconcile user profile schema (B5 of reconcile-historical-add-scripts).
+ *
+ * Captures the union of DDL effects from two historical scripts that ran
+ * against every long-lived env but were never folded into the migration
+ * history:
+ *
+ *   - `scripts/add-user-profile-columns.js` (script #8) — adds `first_name`,
+ *     `last_name`, `username UNIQUE`, `profile_image_url`.
+ *   - `scripts/add-user-profile-fields.js`  (script #9) — adds the same first
+ *     three plus `bio`, `avatar_url`, 10 preference / notification / display
+ *     columns, two new tables (`user_settings`, `user_avatars`), 6 CHECK
+ *     constraints, and 6 indexes.
+ *
+ * Per the convoy's Finding 2, BOTH `profile_image_url` (from #8) AND
+ * `avatar_url` (from #9) coexist in prod and are read by runtime code
+ * (`pages/api/auth/register.js` reads `profile_image_url`; the user/avatar
+ * surface reads `avatar_url`). The redundancy is documented as a separate
+ * follow-up convoy `unify-user-avatar-column`; this migration must NOT pick
+ * one and drop the other.
+ *
+ * Idempotency (D2):
+ *   - Every column ADD uses `ADD COLUMN IF NOT EXISTS`.
+ *   - Both new tables use `CREATE TABLE IF NOT EXISTS`.
+ *   - Every index uses `CREATE INDEX IF NOT EXISTS`.
+ *   - CHECK constraints are wrapped in `DO $$ ... EXCEPTION WHEN
+ *     duplicate_object THEN NULL; END $$;` blocks because Postgres pre-15
+ *     does not accept `ADD CONSTRAINT ... IF NOT EXISTS` for CHECK
+ *     constraints (matches the historical script's try/catch pattern, R5).
+ *
+ * Defaults-backfill DML (the `UPDATE users SET ... WHERE ... IS NULL` block
+ * at the end of script #9) is intentionally NOT replicated. The column
+ * DEFAULT clauses are sufficient on a fresh env (every new row gets the
+ * default at insert time) and prod-existing rows already have the values
+ * from the historical script's run.
+ *
+ * Down-migration is a hard stub. This is a reconciliation migration; rolling
+ * it back on prod would drop columns that runtime code reads.
+ *
+ * @type {import('node-pg-migrate').ColumnDefinitions | undefined}
+ */
+export const shorthands = undefined;
+
+/**
+ * @param {import('node-pg-migrate').MigrationBuilder} pgm
+ * @returns {void}
+ */
+export const up = (pgm) => {
+  pgm.sql(`
+    ALTER TABLE users
+      ADD COLUMN IF NOT EXISTS first_name VARCHAR(255),
+      ADD COLUMN IF NOT EXISTS last_name VARCHAR(255),
+      ADD COLUMN IF NOT EXISTS username VARCHAR(255) UNIQUE,
+      ADD COLUMN IF NOT EXISTS profile_image_url TEXT,
+      ADD COLUMN IF NOT EXISTS bio TEXT,
+      ADD COLUMN IF NOT EXISTS avatar_url TEXT,
+      ADD COLUMN IF NOT EXISTS favorite_games JSONB DEFAULT '["MTG"]',
+      ADD COLUMN IF NOT EXISTS collection_visibility VARCHAR(20) DEFAULT 'private',
+      ADD COLUMN IF NOT EXISTS preferred_currency VARCHAR(3) DEFAULT 'USD',
+      ADD COLUMN IF NOT EXISTS cards_per_page INTEGER DEFAULT 50,
+      ADD COLUMN IF NOT EXISTS default_view VARCHAR(10) DEFAULT 'grid',
+      ADD COLUMN IF NOT EXISTS notifications_email BOOLEAN DEFAULT true,
+      ADD COLUMN IF NOT EXISTS notifications_marketing BOOLEAN DEFAULT false,
+      ADD COLUMN IF NOT EXISTS two_factor_enabled BOOLEAN DEFAULT false,
+      ADD COLUMN IF NOT EXISTS theme VARCHAR(10) DEFAULT 'system',
+      ADD COLUMN IF NOT EXISTS language VARCHAR(5) DEFAULT 'en';
+  `);
+
+  pgm.sql(`
+    CREATE TABLE IF NOT EXISTS user_settings (
+      id SERIAL PRIMARY KEY,
+      user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+      setting_key VARCHAR(100) NOT NULL,
+      setting_value JSONB NOT NULL,
+      created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+      updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+      UNIQUE(user_id, setting_key)
+    );
+  `);
+
+  pgm.sql(`
+    CREATE TABLE IF NOT EXISTS user_avatars (
+      id SERIAL PRIMARY KEY,
+      user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+      filename VARCHAR(255) NOT NULL,
+      original_name VARCHAR(255),
+      mime_type VARCHAR(100),
+      file_size INTEGER,
+      file_path TEXT NOT NULL,
+      is_active BOOLEAN DEFAULT true,
+      created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+      updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    );
+  `);
+
+  pgm.sql(`
+    CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
+    CREATE INDEX IF NOT EXISTS idx_users_email ON users(email);
+    CREATE INDEX IF NOT EXISTS idx_user_settings_user_id ON user_settings(user_id);
+    CREATE INDEX IF NOT EXISTS idx_user_settings_key ON user_settings(setting_key);
+    CREATE INDEX IF NOT EXISTS idx_user_avatars_user_id ON user_avatars(user_id);
+    CREATE INDEX IF NOT EXISTS idx_user_avatars_active ON user_avatars(user_id, is_active);
+  `);
+
+  pgm.sql(`
+    DO $$
+    BEGIN
+      ALTER TABLE users
+        ADD CONSTRAINT check_collection_visibility
+        CHECK (collection_visibility IN ('private', 'public', 'unlisted'));
+    EXCEPTION
+      WHEN duplicate_object THEN NULL;
+    END$$;
+  `);
+
+  pgm.sql(`
+    DO $$
+    BEGIN
+      ALTER TABLE users
+        ADD CONSTRAINT check_preferred_currency
+        CHECK (preferred_currency IN ('USD', 'EUR', 'GBP', 'CAD', 'JPY'));
+    EXCEPTION
+      WHEN duplicate_object THEN NULL;
+    END$$;
+  `);
+
+  pgm.sql(`
+    DO $$
+    BEGIN
+      ALTER TABLE users
+        ADD CONSTRAINT check_cards_per_page
+        CHECK (cards_per_page IN (25, 50, 100));
+    EXCEPTION
+      WHEN duplicate_object THEN NULL;
+    END$$;
+  `);
+
+  pgm.sql(`
+    DO $$
+    BEGIN
+      ALTER TABLE users
+        ADD CONSTRAINT check_default_view
+        CHECK (default_view IN ('grid', 'list'));
+    EXCEPTION
+      WHEN duplicate_object THEN NULL;
+    END$$;
+  `);
+
+  pgm.sql(`
+    DO $$
+    BEGIN
+      ALTER TABLE users
+        ADD CONSTRAINT check_theme
+        CHECK (theme IN ('light', 'dark', 'system'));
+    EXCEPTION
+      WHEN duplicate_object THEN NULL;
+    END$$;
+  `);
+
+  pgm.sql(`
+    DO $$
+    BEGIN
+      ALTER TABLE users
+        ADD CONSTRAINT check_language
+        CHECK (language IN ('en', 'es', 'fr', 'de', 'ja'));
+    EXCEPTION
+      WHEN duplicate_object THEN NULL;
+    END$$;
+  `);
+};
+
+/**
+ * Down-migration is a hard stub. Rolling back this reconciliation would drop
+ * columns that runtime code reads (e.g. `pages/api/auth/register.js` writes
+ * and reads `profile_image_url`; `pages/api/user/settings.js` reads
+ * `theme` / `language` / etc.) and would also drop the `user_settings` and
+ * `user_avatars` tables along with any rows in them. If you need to roll
+ * forward instead, write a NEW dated migration with a real `down`.
+ *
+ * @returns {void}
+ */
+export const down = () => {
+  throw new Error(
+    '[migration:1781000000005_reconcile-user-profile] Refusing to roll back. ' +
+      'This is a reconciliation migration that captures DDL already in prod via ' +
+      'scripts/add-user-profile-columns.js and scripts/add-user-profile-fields.js; ' +
+      'rolling it back would drop columns that runtime code reads (profile_image_url, ' +
+      'avatar_url, theme, language, etc.) and the user_settings / user_avatars tables. ' +
+      'Write a new dated migration if a real schema correction is needed.'
+  );
+};